Frequencies for first 10,000 rows of birwt12 variable in natlterr1997 dataset :

Birthweight |
  Recode 12 |      Freq.     Percent        Cum.
------------+-----------------------------------
          1 |          6        0.06        0.06
          2 |         52        0.52        0.58
          3 |         78        0.78        1.36
          4 |        163        1.63        2.99
          5 |        725        7.25       10.24
          6 |      2,571       25.71       35.95
          7 |      4,141       41.41       77.36
          8 |      1,904       19.04       96.40
          9 |        313        3.13       99.53
         10 |         40        0.40       99.93
         11 |          4        0.04       99.97
         12 |          3        0.03      100.00
------------+-----------------------------------
      Total |     10,000      100.00

by Jean Roth , jroth@nber.org , 22 Dec 2015